We have continued our studies of chromatin structure in the neighborhood of expressed genes. The globin gene family in chicken erythroid cells serves as a model system in which it is possible to study the mechanisms associated with regulation of the individual members of the family during erythroid development. We have continued to study the role played by the general erythroid-specific factor which we have named Eryf1. The cDNA for Eryf1 has been cloned, and we have studied the ability of the protein to serve as a transactivating factor in a variety of cells. The fact that very high levels of transcriptional stimulation are observed in certain cell types provides important information about the mechanism of activation by Eryf1. We have also cloned the cDNA for the human Eryf1. Comparison of the structure and activity of chicken and human proteins provides information both about their evolution and function. To learn more about factors that may act directly on chromatin structure, we have characterized in greater detail the binding of the factor BGP1, which binds to a string of 16 G residues in the adult beta-globin hypersensitive domain. We have also surveyed chromatin of the entire beta-globin domain for nuclease hypersensitive sites. This revealed four candidates for roles as dominant control regions (DCRs). Subsequent experiments in transgenic mice reveal that one of these, the beta-globin enhancer already characterized in our laboratory, has the properties of a DCR. This provides an important potential connection between classical regulatory elements and chromatin structure.